Neurology® E-Pearl of the Week

November 20, 2017

Neurologic Erdheim-Chester disease

Erdheim-Chester disease is a rare non-Langerhans CD68+ histiocytosis that involves the nervous system in 25-50% and has a broad differential diagnosis.1 It primarily affects men in their 5th-7th decade.1 Lesions may develop throughout the neuroaxis and are usually contrast enhancing on MRI. Exophthalmos, retro-orbital pain or blindness may develop in as many as 25% of patients. Brainstem dysfunction, ataxia, diabetes insipidis and seizures are typical neurologic manifestations. Systemic imaging assists the diagnostic evaluation, as long bone, pulmonary, cardiovascular, cutaneous, and retroperitoneal involvement are often present. No standard treatment exists but interferon-alpha is considered first line. Activating mutations of BRAF proto-oncogene are found in approximately 54% of patients, in whom BRAF antagonists such as vemurafenib can be considered.2